Irrigation systems that apply water directly to, or very near, the soil surface, either above the ground or into the air, in discrete drops, continuous drops, small streams, mist, or sprays. These include drip systems, spray systems, jet systems, and bubbler systems. Also referred to as drip, low pressure or low volume irrigation. The efficiencies of these micro-irrigation systems range from 75 to 95 percent, however, an average of 80 percent is commonly used for estimating water requirements.

Source: Corrosion-Doctors.org

Wikipedia:  https://en.wikipedia.org/wiki/Micro-irrigation